Wednesday, October 14, 2009

Rocket Science

A random thought struck me today. In the scenario that a villain is armed with a rocket launcher, and is aiming at you, would it be better to charge forward, or move backward? Assume that no lateral movement is possible, and that the distance is sufficiently close such that the rocket will hit you in seconds at most.

My insight is that moving forward actually reduces the amount of damage you take (if you ignore the salient point that you are likely to die anyway). Note that a rocket is by definition powered. Hence, when in flight, it actually accelerates, which means that if you give it more distance, the rocket gains more speed! The rocket has now a higher kinetic energy on collision. Conversely, by moving forward, the rocket will hit you at a slightly slower speed.

This analysis is, however, not valid for non-powered devices, such as bullets. Bullets will only decelerate, hence it would be wiser to run away in such a case.

This post was inspired by some weapons in comics which gain speed with distance, which on further thought did not seem that improbable after all.